High-impedance amplifier in combination with coated FM windscreen diversity antennas

For the European FM frequency range, a set of four active diversity antennas with high-impedance amplifier is investigated, which are realized in terms of different connections to the conductive coating of a car windscreen. A comparison between simulation and measurement of the screen antennas is carried out and the active frequency responses of all antennas in combination with an optimized high-impedance amplifier circuit are shown. The investigations demonstrate a very powerful performance of the coated screen antenna structures in combination with the high-impedance amplifier compared to a passive quarter wavelength reference antenna. It can be shown that even though the antenna ports offer different impedances, the same amplifier circuit can be used for all these structures. Hence, the use of the high-impedance amplifier concept enables an easy interface, which offers high flexibility in choice of the antenna structures and low development effort for their design.